fuse: add default_request_timeout and max_request_timeout sysctls

Introduce two new sysctls, "default_request_timeout" and
"max_request_timeout". These control how long (in seconds) a server can
tak

fuse: add default_request_timeout and max_request_timeout sysctls

Introduce two new sysctls, "default_request_timeout" and
"max_request_timeout". These control how long (in seconds) a server can
take to reply to a request. If the server does not reply by the timeout,
then the connection will be aborted. The upper bound on these sysctl
values is 65535.

"default_request_timeout" sets the default timeout if no timeout is
specified by the fuse server on mount. 0 (default) indicates no default
timeout should be enforced. If the server did specify a timeout, then
default_request_timeout will be ignored.

"max_request_timeout" sets the max amount of time the server may take to
reply to a request. 0 (default) indicates no maximum timeout. If
max_request_timeout is set and the fuse server attempts to set a
timeout greater than max_request_timeout, the system will use
max_request_timeout as the timeout. Similarly, if default_request_timeout
is greater than max_request_timeout, the system will use
max_request_timeout as the timeout. If the server does not request a
timeout and default_request_timeout is set to 0 but max_request_timeout
is set, then the timeout will be max_request_timeout.

Please note that these timeouts are not 100% precise. The request may
take roughly an extra FUSE_TIMEOUT_TIMER_FREQ seconds beyond the set max
timeout due to how it's internally implemented.

$ sysctl -a | grep fuse.default_request_timeout
fs.fuse.default_request_timeout = 0

$ echo 65536 | sudo tee /proc/sys/fs/fuse/default_request_timeout
tee: /proc/sys/fs/fuse/default_request_timeout: Invalid argument

$ echo 65535 | sudo tee /proc/sys/fs/fuse/default_request_timeout
65535

$ sysctl -a | grep fuse.default_request_timeout
fs.fuse.default_request_timeout = 65535

$ echo 0 | sudo tee /proc/sys/fs/fuse/default_request_timeout
0

$ sysctl -a | grep fuse.default_request_timeout
fs.fuse.default_request_timeout = 0

[Luis Henriques: Limit the timeout to the range [FUSE_TIMEOUT_TIMER_FREQ,
fuse_max_req_timeout]]

Signed-off-by: Joanne Koong <[email protected]>
Reviewed-by: Bernd Schubert <[email protected]>
Reviewed-by: Josef Bacik <[email protected]>
Reviewed-by: Sergey Senozhatsky <[email protected]>
Reviewed-by: Luis Henriques <[email protected]>
Reviewed-by: Jeff Layton <[email protected]>
Signed-off-by: Miklos Szeredi <[email protected]>

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docs: remove duplicate word

- Remove duplicate word, 'to'.

Signed-off-by: Jonathan Corbet <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

fuse: enable dynamic configuration of fuse max pages limit (FUSE_MAX_MAX_PAGES)

Introduce the capability to dynamically configure the max pages limit
(FUSE_MAX_MAX_PAGES) through a sysctl. This allo

fuse: enable dynamic configuration of fuse max pages limit (FUSE_MAX_MAX_PAGES)

Introduce the capability to dynamically configure the max pages limit
(FUSE_MAX_MAX_PAGES) through a sysctl. This allows system administrators
to dynamically set the maximum number of pages that can be used for
servicing requests in fuse.

Previously, this is gated by FUSE_MAX_MAX_PAGES which is statically set
to 256 pages. One result of this is that the buffer size for a write
request is limited to 1 MiB on a 4k-page system.

The default value for this sysctl is the original limit (256 pages).

$ sysctl -a | grep max_pages_limit
fs.fuse.max_pages_limit = 256

$ sysctl -n fs.fuse.max_pages_limit
256

$ echo 1024 | sudo tee /proc/sys/fs/fuse/max_pages_limit
1024

$ sysctl -n fs.fuse.max_pages_limit
1024

$ echo 65536 | sudo tee /proc/sys/fs/fuse/max_pages_limit
tee: /proc/sys/fs/fuse/max_pages_limit: Invalid argument

$ echo 0 | sudo tee /proc/sys/fs/fuse/max_pages_limit
tee: /proc/sys/fs/fuse/max_pages_limit: Invalid argument

$ echo 65535 | sudo tee /proc/sys/fs/fuse/max_pages_limit
65535

$ sysctl -n fs.fuse.max_pages_limit
65535

Signed-off-by: Joanne Koong <[email protected]>
Reviewed-by: Josef Bacik <[email protected]>
Reviewed-by: Sweet Tea Dorminy <[email protected]>
Signed-off-by: Miklos Szeredi <[email protected]>

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vfs: Add a sysctl for automated deletion of dentry

Commit 681ce8623567 ("vfs: Delete the associated dentry when deleting a
file") introduced an unconditional deletion of the associated dentry when a

vfs: Add a sysctl for automated deletion of dentry

Commit 681ce8623567 ("vfs: Delete the associated dentry when deleting a
file") introduced an unconditional deletion of the associated dentry when a
file is removed. However, this led to performance regressions in specific
benchmarks, such as ilebench.sum_operations/s [0], prompting a revert in
commit 4a4be1ad3a6e ("Revert "vfs: Delete the associated dentry when
deleting a file"").

This patch seeks to reintroduce the concept conditionally, where the
associated dentry is deleted only when the user explicitly opts for it
during file removal. A new sysctl fs.automated_deletion_of_dentry is
added for this purpose. Its default value is set to 0.

There are practical use cases for this proactive dentry reclamation.
Besides the Elasticsearch use case mentioned in commit 681ce8623567,
additional examples have surfaced in our production environment. For
instance, in video rendering services that continuously generate temporary
files, upload them to persistent storage servers, and then delete them, a
large number of negative dentries—serving no useful purpose—accumulate.
Users in such cases would benefit from proactively reclaiming these
negative dentries.

Link: https://lore.kernel.org/linux-fsdevel/[email protected] [0]
Link: https://lore.kernel.org/all/20240912-programm-umgibt-a1145fa73bb6@brauner/
Suggested-by: Christian Brauner <[email protected]>
Acked-by: Linus Torvalds <[email protected]>
Signed-off-by: Yafang Shao <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Cc: Linus Torvalds <[email protected]>
Cc: Al Viro <[email protected]>
Cc: Christian Brauner <[email protected]>
Cc: Jan Kara <[email protected]>
Cc: Mateusz Guzik <[email protected]>
Signed-off-by: Christian Brauner <[email protected]>

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docs: admin-guide: sysctl: fix details of struct dentry_stat_t

Commit c8c0c239d5ab moved struct dentry_stat_t to fs/dcache.c but
did not update its location in Documentation, so update that now.
Als

docs: admin-guide: sysctl: fix details of struct dentry_stat_t

Commit c8c0c239d5ab moved struct dentry_stat_t to fs/dcache.c but
did not update its location in Documentation, so update that now.
Also change each struct member from int to long as done in
commit 3942c07ccf98.

Fixes: c8c0c239d5ab ("fs: move dcache sysctls to its own file")
Fixes: 3942c07ccf98 ("fs: bump inode and dentry counters to long")
Signed-off-by: Randy Dunlap <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: [email protected]
Cc: Alexander Viro <[email protected]>
Cc: Christian Brauner <[email protected]>
Cc: [email protected]
Cc: Luis Chamberlain <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Glauber Costa <[email protected]>
Acked-by: Christian Brauner <[email protected]>
Signed-off-by: Jonathan Corbet <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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docs: sysctl/fs: re-order, prettify

This brings the text markup in line with sysctl/abi and
sysctl/kernel:

* the entries are ordered alphabetically
* the table of contents is automatically generate

docs: sysctl/fs: re-order, prettify

This brings the text markup in line with sysctl/abi and
sysctl/kernel:

* the entries are ordered alphabetically
* the table of contents is automatically generated
* markup is used as appropriate for constants etc.

The content isn't fully up-to-date but the obsolete entries are gone,
so remove the kernel version mention.

Signed-off-by: Stephen Kitt <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jonathan Corbet <[email protected]>

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docs: sysctl/fs: remove references to super-max/-nr

These were removed in 2.4.7.8. Remove references to super-max and
super-nr in the sysctl documentation.

Signed-off-by: Stephen Kitt <[email protected]

docs: sysctl/fs: remove references to super-max/-nr

These were removed in 2.4.7.8. Remove references to super-max and
super-nr in the sysctl documentation.

Signed-off-by: Stephen Kitt <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jonathan Corbet <[email protected]>

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docs: sysctl/fs: merge the aio sections

There are two sections documenting aio-nr and aio-max-nr, merge them.
I kept the second explanation of aio-nr, which seems clearer to me,
along with the effec

docs: sysctl/fs: merge the aio sections

There are two sections documenting aio-nr and aio-max-nr, merge them.
I kept the second explanation of aio-nr, which seems clearer to me,
along with the effects of the values from the first section.

Signed-off-by: Stephen Kitt <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jonathan Corbet <[email protected]>

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docs: sysctl/fs: remove references to dquot-max/-nr

dquot-max was removed in 2.4.10.5; dquot-nr was replaced with dqstats
in 2.5.18 which is now /proc/sys/fs/quota. Remove references to
dquot-max an

docs: sysctl/fs: remove references to dquot-max/-nr

dquot-max was removed in 2.4.10.5; dquot-nr was replaced with dqstats
in 2.5.18 which is now /proc/sys/fs/quota. Remove references to
dquot-max and dquot-nr in the sysctl documentation.

Signed-off-by: Stephen Kitt <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jonathan Corbet <[email protected]>

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docs: sysctl/fs: remove references to inode-max

inode-max was removed in 2.3.20pre1, remove references to it in the
sysctl documentation.

Signed-off-by: Stephen Kitt <[email protected]>
Link: https://l

docs: sysctl/fs: remove references to inode-max

inode-max was removed in 2.3.20pre1, remove references to it in the
sysctl documentation.

Signed-off-by: Stephen Kitt <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jonathan Corbet <[email protected]>

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Update Documentation/admin-guide/sysctl/fs.rst

max_user_watches for epoll should say 1/25, rather than 1/32

Signed-off-by: Eric Curtin <[email protected]>
Link: https://lore.kernel.org/r/20210

Update Documentation/admin-guide/sysctl/fs.rst

max_user_watches for epoll should say 1/25, rather than 1/32

Signed-off-by: Eric Curtin <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jonathan Corbet <[email protected]>

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Replace HTTP links with HTTPS ones: Documentation/admin-guide

Rationale:
Reduces attack surface on kernel devs opening the links for MITM
as HTTPS traffic is much harder to manipulate.

Deterministi

Replace HTTP links with HTTPS ones: Documentation/admin-guide

Rationale:
Reduces attack surface on kernel devs opening the links for MITM
as HTTPS traffic is much harder to manipulate.

Deterministic algorithm:
For each file:
If not .svg:
For each line:
If doesn't contain `\bxmlns\b`:
For each link, `\bhttp://[^# \t\r\n]*(?:\w|/)`:
If both the HTTP and HTTPS versions
return 200 OK and serve the same content:
Replace HTTP with HTTPS.

Signed-off-by: Alexander A. Klimov <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jonathan Corbet <[email protected]>

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docs: admin-guide: move sysctl directory to it

The stuff under sysctl describes /sys interface from userspace
point of view. So, add it to the admin-guide and remove the
:orphan: from its index file

docs: admin-guide: move sysctl directory to it

The stuff under sysctl describes /sys interface from userspace
point of view. So, add it to the admin-guide and remove the
:orphan: from its index file.

Signed-off-by: Mauro Carvalho Chehab <[email protected]>

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